Hollow piston pump

ABSTRACT

A positive displacement pump is provided. The pump comprises at least one piston operable to be powered by a power source and to pressurize a fluid. The at least one piston comprises an at least partially hollow piston wherein a flow of fluid is induced into and through the piston and a surrounding piston chamber. The piston preferably comprises a direct-mounted outlet valve for controlling a flow of fluid into and out of the piston.

This non-provisional application claims the benefit of and priority from U.S. Provisional Patent Application Ser. No. 62/476,991, filed Mar. 27, 2017, the entire disclosure of which is hereby incorporated by reference.

FIELD

The present disclosure relates generally to pumps. More specifically, the present disclosure relates to piston pumps and positive displacement pumps. In certain embodiments, the present disclosure relates to positive displacement pumps for pressure washers. It will be recognized, however, that features and devices of the present disclosure are not limited to a particular type of pump or pump application.

BACKGROUND

Conventional positive displacement pumps include those shown and described in U.S. Pat. No. 3,168,872, which is hereby incorporated by reference in its entirety. The general principal behind positive displacement pumps includes providing a power source, such as a motor, that drives at least one reciprocating piston. The reciprocating motion of the piston provides a vacuum or suction force associated with a downstroke of the piston, and a positive pressure when the piston is compressed on the upstroke. The positive pressure provides a compressive force to the fluid and expels the fluid through a high-pressure outlet.

Existing pumps may be acceptable for certain applications. However, there is a constant need and desire to decrease pump size and weight and to increase a pump's power and/or efficiency.

SUMMARY

U.S. Pat. No. 6,514,055 to Schuller, which is hereby incorporated by reference in its entirety, discloses a piston pump having a hollow piston. Schuller, however, fails to disclose various features of the present disclosure including, for example, the hollow piston arrangements of the present disclosure and the provision of inlet or outlet valves at least as shown and described herein.

U.S. Pat. No. 5,022,831 to Gerlach et al., which is hereby incorporated by reference in its entirety, discloses a positive displacement pump with a reciprocating piston. Gerlach et al., however, fail to disclose various novel features of the present disclosure including, for example, the at least partially hollow pistons and associated valve structures of the present disclosure.

In various embodiments, pumps of the present disclosure comprise positive displacement pumps having at least one piston and wherein the at least one piston comprises a hollow or partially hollow piston such that a fluid is allowed to travel within or through the piston. In certain embodiments, one or more pistons of the present disclosure comprise a valve provided on one end of the piston. Preferably, the valve comprises a suction valve that is spring-mounted or otherwise biased and provided on a hollow piston. The suction valve(s) enable and regulate a flow of fluid in and through the hollow piston. Additionally, in certain embodiments of the present disclosure, at least one outlet valve is provided generally in-line with the at least one piston. The outlet valve is preferably provided in or adjacent to an outlet flow path, comprises a spring to bias the outlet valve toward a closed position during a draw cycle of the piston, and is forced open under pressure during the stroke of the piston to enable outflow of pressurized fluid.

In one embodiment, a fluid pump is provided that comprises a housing and wherein the housing comprises a fluid inlet, a fluid outlet, a crankcase, and a cylinder chamber having a predetermined diameter. An elongated piston is provided within the cylinder chamber, wherein the elongated piston is operable to be driven in a reciprocating motion within the cylinder chamber. The elongated piston comprises a hollow portion and an aperture extending through a sidewall of the elongated piston. A first valve is provided on an end of the elongated piston, wherein the first valve is preferably operable to control a fluid flow between an internal volume of the hollow portion of the piston and an internal volume of the cylinder chamber. A second valve is preferably provided at an outlet of the cylinder chamber, wherein the second valve is operable to control a fluid flow between the internal volume of the cylinder chamber and the fluid outlet.

In another embodiment, a fluid pump is provided. The pump comprises a housing with a fluid inlet, a fluid outlet, a crankcase, and a cylinder chamber having a predetermined diameter. An elongated piston is provided within the cylinder chamber, wherein the elongated piston is operable to be driven in a reciprocating motion within the cylinder chamber. The elongated piston comprises a hollow portion and at least one aperture extending through a sidewall of the elongated piston. A first valve is preferably provided on and translatable with an end of the elongated piston, wherein the first valve is operable to control a fluid flow between an internal volume of the hollow portion of the piston and an internal volume of the cylinder chamber. A second valve is preferably provided at an outlet of the cylinder chamber, wherein the second valve comprises a fixed position relative to the cylinder chamber and is operable to control a fluid flow between the internal volume of the cylinder chamber and the fluid outlet of the pump.

In various embodiments, pumps of the present disclosure are adapted for and particularly well suited for pressure washing applications. Although devices and features of the present disclosure are suitable for pressurizing a working fluid (e.g. water) for pressure washing, it will be expressly recognized that pumps, devices and features of the present disclosure are not limited to any particular application. Pumps, as well as components of pumps described herein, are contemplated for use in various applications. Such applications include, but are not limited to, pressure washing, transfer pumping, chemical pumping, irrigation pumping, petrochemical pumping, coffee and espresso machines, etc.

The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the present disclosure. The present disclosure is set forth in various levels of detail in the Summary as well as in the attached drawings and the Detailed Description and no limitation as to the scope of the present disclosure is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary. Additional aspects of the present disclosure will become more readily apparent from the Detailed Description, particularly when taken together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Those of skill in the art will recognize that the following description is merely illustrative of the principles of the disclosure, which may be applied in various ways to provide many different alternative embodiments. This description is made for illustrating the general principles of the teachings of this disclosure and is not meant to limit the inventive concepts disclosed herein.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and together with the general description of the disclosure given above and the detailed description of the drawings given below, serve to explain the principles of the disclosure.

It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the disclosure is not necessarily limited to the particular embodiments illustrated herein.

FIG. 1 is a cross-sectional elevation view of a positive displacement pump according to the prior art.

FIG. 2 is a cross-sectional elevation view of a positive displacement pump according to one embodiment of the present disclosure.

FIG. 3 is a perspective view of a piston according to one embodiment of the present disclosure.

FIG. 4 is a cross-sectional elevation view of the piston of the embodiment of FIG. 3.

FIG. 5 is a perspective view of a pump according to one embodiment of the present disclosure.

FIG. 6A is a perspective view of a pressure washing device provided with a pump according to one embodiment of the present disclosure.

FIG. 6B is a detailed perspective view of the device of FIG. 6A.

FIG. 7 is a perspective view of a pump according to one embodiment of the present disclosure.

FIG. 8 is a cross-sectional elevation view of the pump according to FIG. 7.

FIG. 9 is a perspective view of a pump according to one embodiment of the present disclosure.

FIG. 10 is a cross-sectional elevation view of the pump according to FIG. 9.

FIG. 11 is a perspective view of a pump according to one embodiment of the present disclosure.

FIG. 12 is a cross-sectional elevation view of the pump according to FIG. 11.

FIG. 13A is a partially exploded perspective view of a driving device according to one embodiment of the present disclosure.

FIG. 13B is a perspective view of a component of the driving device of FIG. 13A.

FIG. 14 is a cross-sectional elevation view of a pump piston according to one embodiment of the present disclosure.

FIG. 15 is a perspective view of various components of a pump according to one embodiment of the present disclosure, wherein the components are disassembled for illustrative purposes.

FIG. 16 is a perspective view of a hollow piston according to one embodiment of the present disclosure.

FIG. 17 is a perspective view of a plurality of pistons according to FIG. 16 provided at least partially within a pump housing in accordance with one embodiment of the present disclosure.

FIG. 18 is a perspective view of a piston and valve head according to one embodiment of the present disclosure.

FIG. 19 is a perspective view of a piston according to one embodiment of the present disclosure.

FIG. 20 is a detailed perspective view of the piston according to the embodiment of FIG. 19.

FIG. 21 is a cross-sectional elevation view of the piston according to the embodiment of FIG. 19.

FIG. 22 is a perspective view of a piston according to one embodiment of the present disclosure.

FIG. 23A is a top plan view of the piston according to the embodiment of FIG. 22.

FIG. 23B is an elevation view of the piston according to the embodiment of FIG. 22.

FIG. 24A is a top plan view of the piston according to the embodiment of FIG. 22.

FIG. 24B is an elevation view of the piston according to the embodiment of FIG. 22.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of a positive displacement pump 2 according to the prior art. The pump 2 comprises a low-pressure inlet 4 and a high-pressure outlet 6 for pressurizing and dispensing a fluid. Pumps of the present disclosure, including but not limited to the pump 2 shown in FIG. 1, are operable to pressurize and dispense a fluid (e.g. water) and are useful for operating a pressure-washing device. It will be expressly recognized, however, that the devices and features of the present disclosure are not limited to a particular pump application or to a particular fluid.

Referring again to FIG. 1, a power input 8 is provided and drives a plurality of cams 10. A rotational motion of the cams 10 causes a reciprocating vertical motion of a plurality of pistons 12. Each of the pistons 12 are operable to draw a suction and induce a flow of fluid into the fluid inlet 4. Each of the pistons 12 are also operable to provide a compressive force to the fluid and force the fluid through a flow path 16 and ultimately eject the fluid from the high-pressure outlet 6. A plurality of timing valves 14 are provided. The valves 14 comprise a closed position to allow for a fluid to flow into the piston chambers and an open position to allow a pressurized fluid to be conveyed and ejected from the high-pressure outlet 6. Although not shown in FIG. 1, the power input 8 comprises a drive shaft or socket connectable to a drive shaft wherein a motor or engine provides a torque and rotational motion to the power input 8, which drives the cams 10.

FIG. 2 is a cross-sectional view of a pump 20 according to one embodiment of the present disclosure. The pump 20 comprises a low-pressure fluid inlet 22 and a high-pressure fluid outlet (not shown in FIG. 2, but see 24 of FIG. 5, for example). A power input 26 is provided. The power input 26 preferably comprises at least one of a drive shaft and drive shaft socket to be powered by a power source, such as a motor or engine. The power input 26 provides rotational power to the pump 20, which drives a plurality of cams 28. The cams 28 are provided within a crankcase 29 and each is associated with a piston 32, with three pistons 32 being preferable. The present disclosure and inventions described herein are not limited to any particular number of pistons. It is specifically contemplated that pumps of the present disclosure comprise as few as one piston. It is further contemplated that pumps of the present disclosure comprise a plurality of pistons, including six or more pistons.

The pump 20 of FIG. 2 comprises a suction section comprising a fluid inlet path 36 into which fluid is drawn from the low-pressure inlet 22. The pump 20 further comprises a fluid outlet path 34 through which pressurized fluid is conveyed, and ultimately ejected from the high-pressure outlet. At least one aperture 31 is provided in the sidewall of each of the pistons 32. Each of the distal ends of the pistons 32 comprises a suction valve 33. As shown and described herein, the suction valve 33 is operable to assume an open position on a downstroke or draw of the piston 32, such that the downward draw of the piston 32 creates a suction force to draw fluid from the low-pressure inlet 22 into the suction section 36 and an interior volume of the piston(s) 32 and the cylinder chamber 37 by way of the aperture(s) 31. When a piston 32 reaches a bottom of the stroke, the piston chamber is substantially filled with a fluid by way of the suction drawn during the down stroke. The relevant cam 28 then drives the piston upwardly (at least with respect to the orientation shown in FIG. 2), wherein the suction valve 33 is forced to a closed position by the compression force on the fluid, and the fluid in the piston chamber is forced upwardly and outwardly through the outlet valve 35 and the fluid outlet path 34. The outlet valves 35 correspond to each of the pistons 32, and preferably comprise a spring that biases the outlet valve to a closed position when the piston 32 is in its downstroke and which is forced open when the piston is driven upward. The pump 20 comprises a plurality of valve caps 30 corresponding to each of the pistons 32. The valve caps 30 provide access means which may be selectively removed to access and service the pistons 32, suction valves 33, and outlet valves 35, for example.

The pump 20 of FIG. 2 comprises a high-pressure fluid outlet through which fluid is ejected from the fluid outlet path 34. A pressure relief valve 38 is provided. The pressure relief valve 38 is provided in a closed position during normal operation, such that fluid flow is directed out of the outlet. However, if a predetermined internal pressure of the pump is exceeded (such as may occur if there is an obstruction in the outlet or related dispensing devices), the relief valve 38 is forced open and fluid is recirculated via the recirculation path 39.

FIG. 3 is a perspective view of a piston 32 according to an embodiment of the present disclosure. As shown, the piston 32 comprises a collar member 40 for securing the piston to a drive shaft and/or cam (not shown in FIG. 3). The collar member 40 comprises a rotatable connection 42, such that a shaft 44 of the piston 32 and the collar member 40 are capable of articulating at least with respect to each other. The shaft 44 of the piston 32 comprises an at least a partially hollow shaft and at least one aperture 31. The aperture 31 is operable to be disposed within a fluid flow path of a suction section when assembled within a pump. Fluid is caused to flow into the hollow portion of the piston via the at least one aperture 31. The piston 32 further comprises a suction valve 33 disposed on a distal end of the shaft 44 and having at least one and preferably several apertures 52.

FIG. 4 is a detailed cross-sectional view of the hollow piston 32. The suction valve 33 of FIG. 4 preferably comprises a direct-mounted cage 50. The cage 50 comprises at least one aperture 52 to permit passage of fluid in the sidewall. Preferably, and as shown in FIG. 3, the cage 50 comprises a plurality of apertures in the sidewall and at least one aperture 52 in the upper portion of the cage 50. Provided within the cage 50 is biasing member preferably in the form of a coil spring 54 and a valve stopper 56. The coil spring 54 is operable to bias the valve stopper 56 toward a closed position wherein the valve stopper 56 seals an outlet 57 of the hollow piston. In operation, the valve stopper 56 is forced to an open position while the piston is in a suction or draw state, and is forced to a closed position when the piston is driven and a fluid contained in the piston and chamber is compressed.

The piston of FIG. 4 comprises an at least partially hollow internal volume and an internal conduit 58 for conveyance of fluid. A transverse channel 60 is further provided, wherein the aperture 31 comprises an inlet to the transverse channel 60, which is in fluid communication with the internal conduit 58. As shown in FIG. 4, the channel 60 comprises a through-channel wherein a first aperture 31 a is provided on one side of the piston shaft 44, and a second aperture 31 b is provided on an opposing side of the shaft 44. Accordingly, fluid is allowed to flow into the first aperture 31 a, into the internal conduit 58, and out through the second aperture 31 b. A fluid exiting the second aperture 31 b is preferably provided to any adjacent pistons provided within the pump. A suction section provides a fluid path to the adjacent pistons and surrounds the piston diameter. Certain embodiments of the present disclosure contemplated that only a single piston may be provided within a pump. In such embodiments, one of skill in the art will recognize that the channel 60 need not comprise the outlet 31 b in the sidewall, but rather may simply comprise a first aperture 31 a as an inlet.

FIG. 5 is a perspective view of an assembled pump according to the embodiment of FIG. 2. As shown in FIG. 5, the pump 20 comprises a fluid inlet 22, a fluid outlet 24, and a power input 26. The power input 26 is adapted to be secured to and receive power from an electric motor and drive shaft, for example. The plurality of pistons are provided within the pump housing and are aligned with valve caps 30. The pump 20 of FIG. 5 provides a compact positive displacement pump that is suitable for use with various devices including, but not limited to, pressure washers.

FIGS. 6A-6B are perspective views of the pump 20 of FIG. 5 provided in combination with a pressure washer 70. The pressure washer 70 comprises a frame 72, wheels 74, and an engine 76. The power input of the pump 20 is directly mounted to the engine 76 of the pressure washer, and the pump 20 is operable to pressurize and dispense a fluid from the high-pressure outlet 24 (FIG. 5). As shown, the pump 20 comprises a compact means for pressurizing and dispensing a fluid and does not significantly increase the overall size or weight of an associated pressure washer 70.

FIGS. 7-8 are perspective and cross-sectional elevation views of a pump 100 according to another embodiment of the present disclosure. The pump 100 comprises a similar construction to that of the embodiment of FIG. 2, including a low-pressure inlet 102, a high-pressure outlet 104, and a plurality of pistons 110 within a housing. The pump 100 of FIGS. 7-8 comprises a plastic insert at the suction section 108. The plastic insert, which may comprise nylon, polyoxymethylene, or similar materials, reduces an overall weight of the device 100. Providing the insert and other portions of pumps as plastic components serves to reduce the overall cost of pump devices and of transport of those devices. In areas of the device such as the insert, various plastics have been shown to provide sufficient strength and durability, and enable cost and weight savings in the pump units.

FIG. 9 is a perspective view of a pump 150 according to yet another embodiment of the present disclosure. As shown, the pump 150 of FIG. 9 comprises a similar construction as pumps shown and described herein, and is contemplated as comprising at least one hollow cylinder as shown and described herein. The pump 150 comprises a split cylinder head 152 that is devoid of valve caps. Additional components, including a suction section 154, fluid inlet 156, fluid outlet portion 158, power input 160, and crankcase 162 are provided.

FIG. 10 is a cross-sectional elevation view of the pump 150 shown in FIG. 9. As shown in FIG. 10, the cylinder head 152 comprises a fluid outlet portion within which an outlet valve 168 is provided for each cylinder 164. The construction of the cylinder head 152 with outlet valves 168 at least partially disposed therein, reduces a weight and overall height/size of the pump 150. The cylinder head 152 is secured to the pump 150 by fasteners 151, which are selectively removeable such that the cylinder head 152 can be removed from the pump in order to service internal components.

FIG. 11 is a perspective view of a pump 200 according to another embodiment of the present disclosure. As shown, the pump 200 comprises a fluid inlet 204 and a high-pressure fluid outlet 206. A crankcase 208 is provided, and a plurality of pistons are provided in a suction section 202 and are operable to pressurize a fluid. The crankcase 208 is operable to receive a crankshaft that is integrated with and/or extends from an engine. The crankshaft preferably comprises integrated cams, as shown and described in more detail in FIGS. 13A-13B. FIG. 12 is a cross-sectional elevation view of the pump 200 of FIG. 11. As seen in FIG. 12, each of the pistons provided within the pump 200 comprise contact or bearing surfaces 207 that are operable to be contacted by and driven by cams of a crankshaft (not shown in FIG. 12).

FIG. 13A is a perspective view of an engine 300 suitable for use with the pump according to the embodiment of FIGS. 11-12. The engine 300 comprises a gas-powered engine with a fuel tank 306 and a drive shaft 304. The drive shaft comprises a plurality of cams 302. The cams 302 are operable to drive pistons of a pump, including but not limited to the pump of the embodiment of FIGS. 11-12. The engine 300 of FIG. 13A is provided as one example of a driving device for use with piston cylinders and associated components of the present disclosure. Pump components including valves and piston cylinders as shown and described herein are useful in various applications and devices, and no limitation with respect to pump size, power input devices, etc. is provided herewith.

FIG. 13B is a perspective view of the drive shaft 304 and cam members 302 shown in isolation. The eccentric cams 302 are provided on the drive shaft 304 and are operable to displace pistons of a positive displacement pump. The engine 300 of FIGS. 13A-13B enable the construction and provision of a pump as shown in FIGS. 11-12 wherein the pump 200 is void of a needle or roller bearing, a crankshaft seal, and/or a pump flange, thereby providing for a simplified and low-cost pump 200.

FIG. 14 is a cross-sectional elevation view of a piston 400 and related assembly according to one embodiment of the present disclosure. The piston 400 comprises an internal conduit 408 for fluid, and the pump in which the piston is provided comprises a transverse channel 402 to allow for ingress of low-pressure fluid into the piston 400 from the inlet. A first aperture 406 a and a second aperture 406 b are provided on opposing sides of a shaft of the piston 400 to enable fluid flow in and through the piston. A cage valve 410 is provided on a distal end of the piston 400. The cage valve 410 comprises a coil spring 412 and a valve stopper 414 to control a flow of fluid through the distal end of the piston. The coil spring 412 and the valve stopper 414 are operable to be provided in an open position on a downstroke of the piston 400, thereby enabling and allowing the internal conduit 408 of the piston 400 and an upper chamber 416 to fill with fluid when the piston is drawing a vacuum. The cage valve 410 preferably comprises a plurality of openings to permit fluid flow between the internal conduit 408 and the upper chamber 416, while also providing a surface upon which the coil spring 412 can exert a force and bias the valve stopper 414 toward a closed or sealed position.

As shown in FIG. 14, the piston 400 comprises a through-channel wherein a first aperture 406 a is provided on one side of the piston shaft, and a second aperture 406 b is provided on an opposing side of the shaft. Accordingly, fluid is allowed to flow into the first aperture 406 a, into the internal conduit 408, and out through the second aperture 406 b. A fluid exiting the second aperture 406 b is preferably provided to adjacent pistons provided within the pump. The channels 402, 404 provide a fluid path to the pistons, and surround the piston diameter(s).

The pump of the embodiment of FIG. 14 also comprises a high pressure outlet section 420. An outlet valve 418 is provided and associated with each piston 400 to control fluid flow between the piston 400 and the chamber 416 to the high-pressure outlet. The outlet valve 418 shown in FIG. 14 comprises a cage valve comprising a cage 422, a coil spring 424 and a valve stopper 426. The outlet valve 418 comprises a similar construction to that of the cage valve 410, but generally operates in an inverse manner. Specifically, when the piston 400 is provided in a suction state or downstroke, the cage valve 410 is provided in an open position and allows fluid to flow into the piston 400 and chamber 416. During this downstroke, the outlet valve 418 is provided in a closed position due in part to the coil spring 424 forcing the valve stopper 426 to a closed or sealed position. This arrangement allows the internal conduit 408 of the piston 400 and the upper chamber 416 to fill with fluid without allowing fluid to pass into the high pressure outlet section 420. In a pressurized state, wherein the piston 400 is driven upwardly (at least with respect to the position shown in FIG. 14), the valve seat 414 is forced to a closed position and the pressure transmitted through the fluid in the pump forces the outlet valve 418 to an open position wherein the spring force of the coil spring 424 is overcome, the valve stopper 426 is forced open, and a pressurized fluid is allowed to flow through the high pressure outlet section 420 to the high pressure outlet (not shown in FIG. 14). As will be recognized by one of ordinary skill in the art, this process will repeat itself in an iterative fashion based on reciprocating motion of the piston that is induced by an engine or motor.

FIG. 15 is a perspective view of various components of a positive displacement pump according to one embodiment of the present disclosure. The components provided in FIG. 15 are detailed views of the components of the embodiment of FIGS. 9-10, but may also be provided in additional embodiments of the present disclosure. As shown, a cylinder head 434 is provided that comprises a suction section 430. Upper portions 432 of the piston chamber are shown in isolation.

A plurality of cages 410 are provided for construction of the cage valves (see FIG. 14). A plurality of seals or races 438 are provided, with each being adapted to receive a piston, and each permits translation of the piston therethrough and seal the suction chamber 430. A piston shaft 405 is also shown, wherein the piston shaft comprises a hollow piston shaft having a through-aperture 406. A valve seat 414 is depicted, wherein the valve seat 414 is operable to at least partially control the flow of fluid in and out of the hollow piston. The valve seat 414 is operable to impacted or biased by a coil spring, wherein one end of the coil spring acts on the valve seat 414 and a second end of the coil spring is provided against a cage 410.

FIG. 16 is a view of a piston 400 and a portion of a cam follower 440. The piston 400 comprises a shaft that is at least partially hollow and comprises an aperture 406 to permit fluid flow. The cam follower 440 is connected to the piston shaft at a hinge 442 to convert a somewhat rotational motion of a drive shaft and the cam follower 440 to a mostly linear motion of the piston 400.

FIG. 17 is a perspective view of a partially constructed pump 450 having a crankcase 452 and a plurality of hollow pistons 400 extending therefrom. Various embodiments of the present disclosure contemplate three pistons provided in series. It will be recognized, however, that alternative arrangement and embodiments contemplate the provision of greater than or fewer than three pistons, as well as alternative spacing and arrangement of the pistons.

FIG. 18 is a perspective view of a piston 500 according to another embodiment of the present disclosure. As shown, the piston 500 comprises an at least partially hollow piston member with apertures 504, 506 provided in opposing sidewalls of the piston body to permit fluid flow into a hollow portion 510 of the piston. The piston 500 comprises a valve cap 502 that is interconnected to at least one and preferably two support arms 508 a, 508 b. When the piston is provided in a vacuum or suction state, the valve cap 502 is drawn to an open position, and distal ends of the support arms 508 are translatable within the apertures 504, 506. Distal ends of the support arms 508 contact an interior surface 505 of the apertures 504, 506. The support arms 508 are also connected to the valve cap 502 to prevent the valve cap 502 from being dislodged from the piston when the piston is in a suction state. In a pressurized state, a fluid provided in a chamber above the valve cap 502 (not shown in FIG. 18) provides a compressive force to the valve cap 502 and seals the valve cap 502 to the piston. The support arms 508 thus comprise “catch” members to prevent dislocation of the valve cap 502 in suction, and which assume a generally passive state when the piston is provided in compression.

The valve cap 502 preferably comprises a conical or frustoconical member that is displaceable between open and closed position to control a fluid flow through the hollow piston 500. When the piston 500 is provided in a vacuum state, the piston head 502 is provided in an open position wherein fluid is allowed to flow from the hollow portion 510 to a piston chamber space provided above the piston. When the piston is driven to force a fluid, the piston head 502 is provided in a closed position to provide an arrangement suitable for driving and pressurizing a fluid and expelling fluid from the piston chamber.

FIG. 19 is a perspective view of a piston 600 according to another embodiment of the present disclosure. As shown, the piston 600 comprises an at least partially hollow piston with a shaft 604 and at least one aperture 605 provided in the shaft. The aperture 605 is operable to receive a fluid from a low-pressure inlet of a pump and ultimately transmit the fluid through the interior volume of the piston. One end of the piston 600 is in communication with a drive shaft and/or cam of a pump, and the second end of the piston comprises at least one outlet 608 to expel fluid from the piston 600 in a high-pressure section of the pump. A valve assembly is provided at the second end of the piston. The valve assembly, as will be shown and described herein, comprises a locking member 606 to secure a valve cap and a spring.

As shown in more detail in FIGS. 20-21, the second end of the piston 600 comprises a valve cap 612 which is biased toward a closed position by biasing member in the form of a coil spring 610. The valve cap 612 and the coil spring 610 are held in place by the locking member 606. Specifically, the locking member comprises a plurality of extensions 609. One end of the spring 610 is provided in force-transmitting communication with the underside of at least one of the extensions 609. A second end of the spring is provided in force-transmitting communication with the valve cap 612 to bias the valve cap 612 toward a closed position wherein the piston chamber is closed or sealed at the upper end. The extensions 609 also provide a means to secure or lock the locking member 606 in place and secure the various components to the piston 600. As shown in FIG. 20, the extensions 609 are selectively positionable with respect to a contoured upper end of the piston 600. Specifically, the locking member 606 is selectively positionable between a locked and unlocked state by way of rotation of the locking member 606 about a vertical axis. The locking member 606 comprises an opening 607 in its upper end to accommodate a screwdriver, a key, or similar tool, and to allow for rotation of the locking member 606 between a locked or secured state and an unlocked or unsecured state. Locking members 606 of the present disclosure provide a means for quickly and easily disassembling components of the pistons in the event that such components require service, cleaning, replacement, etc.

As shown in FIG. 21, the valve cap 612 comprises an upstanding or domed center portion which is operable to receive and align the spring 610. The domed portion also provides structural integrity to the valve cap 612. The valve cap 612 is biased toward a closed position (as shown in FIG. 21), and is displaceable between an open position and closed position. When the piston is provided in a suction mode (i.e. the during the downstroke of the piston), the valve cap 612 is forced to an open position wherein fluid is drawn into the aperture 605, the internal volume of the piston 600, and wherein the fluid fills a chamber space by flowing through the at least one outlet 608 provided on the second end of the piston. The spring 610 is operable to bias the valve cap 612 toward a closed position. When the piston 600 is driven to provide a compression to a fluid, the valve cap 612 is forced to a closed position wherein the internal volume 614 of the piston 600 is sealed and fluid that previously translated through the aperture 608 is forced through a high-pressure section of the pump and expelled as a pressurized fluid.

FIG. 22 is an exploded perspective view of a piston 600 according to the embodiment of FIG. 19. As shown, the locking member 606 comprises a plurality of extensions and preferably four extensions 609 that are operable to secure the locking member, the spring 610 and the valve cap 612. The extensions also provide a contact surface for the coil spring 610. The plurality of extensions 609 are operable to contact and communicate with a contoured upper portion of the piston 600.

FIGS. 23A-23B depict the piston 600 of FIG. 22 in an assembled and unlocked state. As shown in FIG. 23A, the plurality of extensions 609 are provided in alignment with convex portions 618 of the upper end of the piston 600, thereby allowing insertion of the locking member 606 within the upper end of the piston 600. FIGS. 24A-24B depict the piston and various components in an assembled and locked state. With reference to FIG. 24A, the locking member 606 is provided in a locked state by rotating the locking member 606 about a substantially vertical axis and by about ninety degrees until the protrusions 609 are provided beneath and in force-transmitting communication with concave portions 611 (see FIG. 23A) of the piston. In some embodiments, the protrusions 609 comprise rounded or curved upper surface, and the concave portions 611 comprise a rounded lower edge to receive and correspond with the rounded or curved upper surface of the protrusions. FIG. 24A provides a piston and valve assembly in a locked or secured state wherein the piston is capable of functioning in its intended manner to pressurize a fluid.

Various features and embodiments of pumping devices are provided herein. It will be recognized, however, that various features are not necessarily specific to certain embodiments and may be provided on any one or more embodiments. The present disclosure and embodiments provided herein are not mutually exclusive and may be combined, substituted, and omitted. The scope of the invention(s) provided herein is thus not limited to any particular embodiment, drawing, or particular arrangement of features.

While various embodiments of the present disclosure have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present disclosure. Further, the invention(s) described herein are capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purposes of description and should not be regarded as limiting. The use of “including,” “comprising,” or “adding” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof, as well as, additional items. 

What is claimed is:
 1. A fluid pump comprising: a housing having a fluid inlet, a fluid outlet, a crankcase, and a cylinder chamber having a predetermined diameter; an elongated piston translatable within the cylinder chamber; wherein the elongated piston is operable to be driven in a substantially reciprocating motion within the cylinder chamber; wherein the elongated piston comprises a hollow portion and an aperture extending through a sidewall of the hollow portion of the elongated piston; a first valve provided on an end of the elongated piston, wherein the first valve is operable to control a fluid flow between an internal volume of the hollow portion of the piston and an internal volume of the cylinder chamber; and a second valve provided at an outlet of the cylinder chamber, wherein the second valve is operable to control a fluid flow between the internal volume of the cylinder chamber and the fluid outlet of the pump.
 2. The fluid pump of claim 1, wherein the fluid pump comprises a plurality of elongated pistons.
 3. The fluid pump of claim 1, wherein the first valve comprises a spring-loaded valve mounted to an end of the elongated piston.
 4. The fluid pump of claim 1, wherein the second valve comprises a spring-loaded valve.
 5. The fluid pump of claim 1, wherein the aperture of the elongated piston is provided within a fluid flow path.
 6. The fluid pump of claim 1, wherein the elongated piston comprises a second aperture extending through a sidewall of the elongated piston such that fluid is allowed to pass through the elongated piston.
 7. The fluid pump of claim 1, wherein the first valve comprises a biasing member, and wherein the first valve is operable to be provided in a closed position while the elongated piston is translated in a first direction and is operable to be provided in an open position while the elongated piston is provided in a second direction.
 8. A fluid pump comprising: a housing having a fluid inlet, a fluid outlet, and a cylinder chamber; an elongated piston translatable within the cylinder chamber; wherein the elongated piston is operable to be driven in a substantially reciprocating motion within the cylinder chamber; wherein the elongated piston comprises a hollow portion and an aperture extending through a sidewall thereof, the aperture allowing for fluid to communicate with the hollow portion; a valve provided on an end of the elongated piston, wherein the valve is operable to control a fluid flow to and from the hollow portion of the piston; the valve comprising a biasing member that is operable to bias the valve toward a closed position.
 9. The fluid pump of claim 8, wherein the valve is operable to control a fluid flow between the hollow portion of the piston and an internal volume of the cylinder chamber.
 10. The fluid pump of claim 8, wherein the biasing member comprises a spring.
 11. The fluid pump of claim 8, wherein the fluid pump comprises a plurality of elongated pistons.
 12. The fluid pump of claim 8, wherein the valve comprises a cage valve mounted to the elongated piston.
 13. The fluid pump of claim 8, further comprising a second valve provided at an outlet of the cylinder chamber, wherein the second valve is operable to control a fluid flow between an internal volume of the cylinder chamber and the fluid outlet of the pump.
 14. The fluid pump of claim 8, wherein the aperture of the elongated piston is provided within a fluid flow path of the housing.
 15. The fluid pump of claim 8, wherein the elongated piston comprises a second aperture extending through a sidewall of the elongated piston.
 16. A fluid pump comprising: a housing having a fluid inlet, a fluid outlet, and a cylinder chamber; an elongated piston translatable within the cylinder chamber; wherein the elongated piston is operable to be driven in a substantially reciprocating motion within the cylinder chamber; wherein the elongated piston comprises an internal volume having a hollow portion and an aperture extending through a sidewall thereof; a valve provided on a distal end of the elongated piston, wherein the valve is operable to regulate a fluid flow between the cylinder chamber and the internal volume of the piston; the valve comprising a biasing member that is operable to bias the valve toward a closed position, wherein fluid is not allowed to flow through the valve, and wherein the valve is operable to be provided in an open position when the elongated piston is provided in a suction state.
 17. The fluid pump of claim 16, wherein the fluid pump comprises a plurality of elongated pistons.
 18. The fluid pump of claim 16, wherein the valve comprises a cage valve mounted to the elongated piston.
 19. The fluid pump of claim 16, further comprising a second valve provided proximal to an outlet of the cylinder chamber, wherein the second valve is operable to control a fluid flow between an internal volume of the cylinder chamber and the fluid outlet of the pump.
 20. The fluid pump of claim 16, wherein the elongated piston comprises a second aperture extending through a sidewall of the elongated piston. 